Heretofore, a manual valve has been employed in a semiconductor manufacturing device, for example, as a chemical liquid valve for controlling the flow of a chemical liquid to be supplied to a chemical liquid supply unit or as a chemical liquid collecting valve or the like for sampling a chemical liquid. Some of the such manual valves are designed such that a valve element is moved by rotation of a knob through a rod (see Patent Literatures 1 and 2).
An explanation of a manual valve disclosed in the Patent Literature 1 is now given referring to FIG. 19.
A manual valve 301A is formed with a valve main body 303, a diaphragm retainer 304, a cylinder 305, a diaphragm valve element 309, a valve rod 310, a knob 312A, and others. The diaphragm valve element (valve element) 309 includes a peripheral portion firmly held between the valve main body 303 and the retainer 304 and also includes a center portion threaded with the valve rod 310. The valve rod 310 is continuously urged upward by a spring 311. The knob 312A is threadedly engaged with the cylinder 305 so that the knob 312A internally contacts with an upper end of the rod 310.
In the manual valve 301A of the Patent Literature 1, when the knob 312A is turned to move upward/downward as being held in contact with the valve rod 310, this rod 310 is moved in an opening/closing direction against the urging force of the spring 311, so that a valve opening degree can be adjusted.
A manual valve disclosed in the Patent Literature 2 is explained referring to FIG. 20.
A manual valve 401 is formed with a handle (knob) 411, a sliding nut 413, a piston 423, a metal spring 426, a valve element 433, a valve seat 434, and others.
A thread portion 413a of the sliding nut 413 is threadedly engaged with a thread portion 423a of the piston 423 to connect the nut 413 with the piston 423 so that the nut 413 is rotated together with the handle 411. The valve element 433 includes a peripheral end portion 433a firmly held between a valve main body 431 and a lower piston cylinder 422 and also has a center portion integrally connected with the piston 423. The piston 423 is continuously urged downward by the spring 426.
In the manual valve 401 of the Patent Literature 2, when the handle 411 is rotated in a valve closing direction, the piston 423 is moved downward by screw feeding with respect to the sliding nut 413 to bring the valve element 433 downward into contact with the valve seat 434 by the urging force of the spring 426. When the valve element 433 is placed in contact with the valve seat 434 into a valve closing position, the thread portion 413a of the sliding nut 413 and the thread portion 423a of the piston 423 are disengaged and the handle 411 turns free.